It has been well known that a polysaccharide such as starch, dextran, cellulose, cellulose derivatives and the like exhibit respective unique optical resolving powers. Particularly, it has already been found that cellulose derivatives prepared by esterifying the hydroxyl groups of cellulose, i.e., chemically modified celluloses such as cellulose triacetate and the like are superior to cellulose itself in respect of optical resolving power.
When a substance as described above having an optical resolving power is as such used as a packing for liquid chromatography in the direct resolution of an optical isomer mixture by liquid chromatography, the service conditions of the column are disadvantageously narrowed, because the packing composed of the substance is poor in pressure resistance and is swollen or shrunken with the solvent used. In order to overcome this advantage, it is generally thought a means that the substance is supported on a support free from such problematic properties and the product is used.
Under these circumstances, the impregnation-adsorption process, i.e., a physical process which comprises dipping a support in a solution of the above substance, recovering the support and drying it occurs to us as one of the easiest processes for supporting the substance. However, the disadvantage still remains that only few kinds of solvents are usable when a measurement and an operation is conducted with a chromatograph, because it is undesirable to use a solvent which dissolves the substance. This disadvantage is generally more significant when a chemically modified polysaccharide is used. That is, the developer to be used in the chromatography using the modified polysaccharide must be one which does not dissolve the modified polysaccharide, because of the high solubility of the modified polysaccharide in an organic solvent, which restricts the selection of the resolution conditions severely. Further, there is also a limitation in the selection of the solvent to be used for dissolving a sample, because a chemically modified polysaccharide has a problem that the number of theoretical plates thereof is remarkably lowered even by the injection of only several microliters of a good solvent therefor.
Although the chemical bonding of a polysaccharide derivative as described above to a support may be thought to be effective in overcoming the above disadvantage of the physical process, no specific means have been proposed as yet on how to chemically bond the polysaccharide derivative to a support while maintaining the excellent optical resolving power of the polysaccharide derivative. For example, although Japanese Patent Publication-A No. 82858/1985 discloses that a chemical process as well as a physical one can be employed in supporting a polysaccharide derivative on a support, no specific description on the chemical process is found in this patent document.